Power transmission



y 4, 9" A. L. ELLIS 2,164,647

POWER TRANSMISSION Original Filed Sept. 27, 1935 9 Sheets-Sheet l INVENIUR;

ART/ UP L. ELLIS ATTORNEY.

July 4, 1939. A. ELLIS POWER TRANSMISSION Original Filed Sept. 27, 1935 9 Sheets-Sheet 3 5 e\ 7 3 y 5 5 A- m 5 u s s O 4 zz 4 5 K ATTORNEY.

July 4, 1939. A. ELLIS 2,164,647

POWER TRANSMISSION Original Filed Sept. 2'7, 1935 9 Sheets-Shee't 4 lee INVENTOR.

ARTHUR L. ELL/5 ATTORNEY.

July 4, 1939.

A. ELLIS 2,164,647

POWER TRANSMISSION Original Filed Sept. 27, 1935 9 Sheets-Sheet 5 Z3 24' 3 v 3 24- 22 7 27 I 29- 7 INVENTOR.

ARTHUR L. ELL/5 Mi/Tim ATTORNEY July 4, 1939. A L Ems 2,164,647

POWER TRANSMI S SION 9 Sheets-Sheet 6 I Original Filed Sept. 27, 1955 INVENTOR.

' ARTHUR L.. ELL/5 ATTORNEY.

y 4, 1939- A. L. ELLIS 2,164,647

POWER TRANSMISSION Original Filed Sept. 27, 1935 9 Sheets-Sheet '7 Aneruwv L. ELLIS ATTORNEY.

July 4, 1939. A. L. ELLIS 2,164,647

POWER TRANSMISSION Original Filed Sept. 27, 1935 9 Sheets-Sheet 8 i I33 /65 I33 l /L 1: W 5% r 4; A

l j] C,- 137 (5 -135 I 203 7/ V INVENTOR ARrHuR L. ELL/5 ATTORNEY July 4, 1939. A, LLE; 2,34,,647

POWER TRANSMISSION Original Filed Sept 27, 1935 9 Sheets-Sheet 9 INVENTOR AfirHuR L. ELLIS @QAXM ATTOR/VE Y Patented July 4, 1939 UNITED STATES PATENT OFFICE POWER TRANSMISSION Application September 27, 1935, Serial No. 42,429

, Renewed December 1, 1938 14 Claims.

This invention relates to power transmissions and more particularly hydraulic operating and control systems for systems of the indicated type designed for the operation and control of heavy duty machines such as presses adapted for the working of large sheets of metal utilized for instance in the construction of metal automobile bodies and the like. The invention contemplates primarily the provision of a novel hydraulic operating and control system or circuit for such machines whereby a maximum flexibility in the operation and control thereof is rendered possible and whereby the full tonnage or equivalent eifect of the machine may be selectively exerted at any point in the operative cycle thereof.

Certain intricate and extremely large stampings require the use of not only a large capacity press but one which has a plurality of separately movable reciprocating slides for accomplishing a 0 plurality of stamping operations at one time in a single press. Where the maximum effort which the press must exert is of the order of a thousand tons and three or more independently movable slides must be used, the use of a mechanically operated press, that is, for example, one in which the slides are reciprocated by one or more crankshafts and toggle and connecting rod linkages, entails many disadvantages. Due to the large investment in a press of so large a size,

9 it is extremely desirable that the press be adaptable to many different types of press operations and exhibit a high degree of flexibility in the operating cycles thereof, so that it will not be rendered obsolete before the endof its useful life by change in the design of the stampings which are produced by the press. diflicult to achieve in a mechanically operated press due to the limitations imposed by a mechanical linkage of any sort. With a mechanical press the operating cycle of each slide is to quite an extent invariable and therefore seriously restrictive to the usefulness of a mechanical press for manufacture of a wide variety of articles.

While it has long been known that hydraulic presses offered several advantages over mechanical presses in the way of flexibility of adjustment to meet various operating requirements and in increased die life, the high cost of the necessary This flexibility is of the press may be secured at reasonable cost.

It is also an object to provide a hydraulic operating means for a multiple action press of large size which will provide sufficient power for a maximum instantaneous load on, the press while 5 permitting the use of a hydraulic pump smaller than would ordinarily be required to accommodate the maximum instantaneous load.

A further object of the invention is to arrange the hydraulic system or circuit in a manner to enable different parts of the machine to be independently operated at will and to enable any one section or any combination of sections thereof to be efliciently operated and controlled in predetermined relationship.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings: 7

Figures 1 and 1a are diagrammatic views which together illustrate the novel hydraulic system or circuit and control applied to a press;

Figure 2 is a fragmentary view exemplifying 25 the press;

Figure 3 is a schematic sectional elevation thereof;

Figure 4 is a schematic horizontal section of the press;

Figure 5 is a detail plan view of a hydraulic pump and its control with parts in section as used in the novel system or circuit;

Figure 6 is an elevation of said pump partly in section; 35

Figure 7 is a plan view of a reverse valve included in the circuit;

Figure 8 is a sectional elevation thereof;

Figure 9 is a cross-section on the line 9-9 of Figure 8;

Figure 10 is a detail section illustrating a pilot control valve such as is used in the circuit;

Figure 11 is a detail sectional view of a check valve forming part of the circuit;

Figure 12 is a detail side view, partly in section, 45 of a hydraulic accumulator forming part of the invention;

Figure 13 is a sectional view showing another pilot control valve used in the circuit;

Figure 14 is a diagrammatic view showing the operating mechanism for the various pilot control valves;

Figure 15 is a sectional view showing another pilot control valve used in the circuit.

For purposes of illustration and description the novel hydraulic operating and control system has been shown as applied to a press designed for heavy duty for which said system is special ly adapted; it is however to be distinctly understood that such illustration .and description is not intended to define the limits of utility of the novel system which, as will. be apparent, may be eificiently applied to other types of machines.

The press which has been selected to exemplify the type of heavy duty machines for which the novel hydraulic system and control are specially adapted is diagrammatically illustrated in Figures 2, 3 and a, and in such illustrated form consists of an upright frame 5 5 of conventional construction provided with guides l6 arranged in opposed parallel pairs and extending vertically of the frame l5 for guiding the first or main blank holder ii in its vertical movements. The illustrated press further includes a second or auxiliary blank holder is adapted to move vertically within and relatively to the blank holder ll which as shown, may be of open form to permit such operations. In addition the press shown in the drawings is provided with a press table 09 which is also movable in vertical directions lengthwise of the guides it as indicated in Figures 2 and 3; The means for operating the blank holder it as shown in the drawings consists of two shafts. 2d suitably journalled on the frame 115 in spaced parallel relation and provided with arms 2!! which pro- J'ect radially inward from and are fixed upon said shaft 20. Similar arms 22 are secured upon said shafts 22 in outwardly extending radial relation thereto and are pivotally connected at 23 with links 24 which themselves are pivotally connected at 25 to lugs 26 projecting upwardly from the main blank holder ll. As shown in Figure 3 tubular sleeves Z'l are rotatably mounted upon the shafts 20 and are provided with inwardly directed arms 28 (Figure 4) and with outwardly directed arms 29. The latter are pivotally connected at 36 with links Bl which in turn are pivotally connected at 32 with lugs 33 extending upwardly from projections 34 carried by the sec-- 0nd or auxiliary blank holder ill as illustrated in Figures 2 and 3. For the purpose of assisting in maintaining the press table I12 properly lined up, a toggle arrangement may be provided, said arrangement comprising a shaft 35 suitably journalled in the machine and carrying one or more arms 38 as shown in Figures 2 and 3. The toggle arrangement further consists of links 3! each pivoted at 38 to an arm 36 and at 39 to lugs 40 depending from the press table ill.

The rocking of the shafts 28 to manipulate the arms 22, links 24 and asosciated elements in a manner to eifect the desired operation of the first or main blank holder H, is accomplished by means of a pressure ram or plunger ll slidable in a pressure cylinder 42, and a return piston 43 reciprocable in a return cylinder l t. In practice the pressure ram Q! and the return piston 63 preferably comprise parts of a hydraulically operated unit which carries a coupling means illustrated in the form of oppositely extending members d5; the latter are pivotally connected with links 26 which in turn are pivotally connected with the previously mentioned arms 2!. tubular sleeves 27 to develop the desired operation of the second or auxiliary blank holder [IS likewise consists of a pressure ram or plunger ll and a cooperating return piston E8 slidable respectively in a pressure cylinder i9 and return cylinder as shown in Figure 3. The unit Gon The means for rocking the sisting of the combined ram and piston 18 also carries a coupling means shown in the form of oppositely directed members at pivotally connected with links 52 which in turn are pivotally connected with the previously mentioned arms 28 as illustrated in Figure 3. Forsimplicity in the circuit diagram the units lll$3 and lll8 are shown inverted in Fig. 1.

The press table l 9 is supported upon a plurality of pressure rams or plungers 53 reciprocable in pressure cylinders 5G and further is provided with a plurality of return pistons 55 slidable in return cylinders 56 as shown in Figures 2 and 3.

As shown diagrammatically in Figure l a pipe line 57! leads from the pressure cylinder 32 to the port 580i a hydraulically operated four-Way reversing valve the details'of which, as illustrated in Figures '7, 8 and 9, will be more fully set forth hereinafter. A similar pipe line Ell extends from the return cylinder M to the port iii of a hydraulically operated check valve t2, and continues from a second port 63 of said check valve 62 to a port lid of the reversing valve 59; the check valve 62 is shown in detail in Figure 11 and will be more fully described hereinafter.

The pressure cylinder 59 is connected by means of a pipe line 51a with the port 58a of a second hydraulically operated four-way reversing valve 5% similar in construction and operation to the valve 59, While the return cylinder 50 is connected by means of a pipe line 60a with the port Ma. of the reversing valve 5911 as diagrammatically illustrated in Figure l.

By means of pipe line 51b and branch pipes leading therefrom, the pressure cylinders 54 are connected with the port 5811 of a third hydraulically operated four-way reversing valve 5% which also corresponds in construction and operation to the valve 59. The return cylinders 56 in turn are connected through the medium of a pipe line tub with the port Ma of a second hydrau lically operated check valve 62a, said pipe line 60b continuing from a second port 63m of said check valve fiiZa to the port 8417' of the reversing valve 596; the check valve 62a may be similar in construction and operation to the check valve 62 which, as previously stated herein, will be described in detail hereinafter.

The reversing valves 59, 59a: and 5% are provided with high pressure ports 65, 65a. and 652) respectively which are connected with each other by a pipe line 66, and further include low pressure ports Bl, El a and Ei'lbrespectively which are con nected with each other by a pipe line 68 as diagrammatically illustrated in Figure 1.

The high pressure line 66 is connected by means of a pipe line 69 and a branch pipe 69a. with the corresponding ports l0 and 10a respectively of two hydraulic variable delivery pumps H and Ma as shown in Figurela. In the preferredarrangement suitable check valves '32 and 720: are located in the pipe line 69 and branch pipe 69m respectively in proximity to the ports 70 and 70a to prevent back pressure through the latter. An example of the check valves l2 and 12a is shown in detail in Figure 6. For purposes of control the pipe line 69 and branch pipe 69a may each be provided with suitable shut-off valves 73 and 73a. respec" tively, as indicated in Figure la. The pumps it and 'ula. may be duplicates of each other in construction and operation and are illustrated on an enlarged scale, with their asociated elements, in Figures 5 and 6. These pumps will be referred to more fully hereinafter. As diagrammatically illustrated in Figure 1a, a branch pipe 41 leads (ill from the pipe line 69 to the oil or equivalent cylinder I of a high pressure accumulator system A, which may be of any suitable type and as shown, is of the air operated type including a compressed air tank I6 connected with the accumulator proper I5 by means of a pipe 11. The construction of the accumulator system A is illustrated in Figure 12 and will be later described. It is capable of accumulating and releasing hydraulic energy.

The low pressure line 68 is connected by means of a pipe line I8 and branch pipe 18a with the second ports I9 and 19a respectively of the two pumps II and Na as indicated in Figure 1a. For purposes of control the pipe line I8 and branch pipe 1811 may each be provided with shutofl valves 80 and 80a respectively. A branch pipe 8| connects the pipe line I8 with a low pressure accumulator B while another branch pipe 8Ia leads from the pipe line 68 to a second low pressure accumulator C which is also connected with the branch pipe 18a by means of a branch connection 8Ib. .The low pressure accumulators B and C may also be of any conventional type and as shown are of the same general type as accumulator A including the accumulators proper 82 connected with cooperating compressed air tanks 83 by pipes 84..

The operation of the reversing valves 59, 59a and 59b is eflected and controlled in the desired manner by means of pilot or control valves 85, 85a and 85b respectively, in a manner to be more particularly pointed out further on in the description; an example of such pilotor control valves being shown in detail in Figure 10. In. the illustrated example the pilot or control valve 85 has a port 86 connected by means of a pipe 81 with a cylinder 88 forming part of and projecting from one end of. the reversing valve 59, and further is provided with another port 89 which is connected by means ofa pipe 90 with a second cylinder 9| forming part of and projecting from the opposite end of the reversing valve 59 as shown in Figure 1. In addition the pilot valve 85 includes a port 92 which is connected by means of a pipe 93 with the low pressure line 68, and another port 94 from which pipes 95, 91 and 98 lead to an oil tank 96 shown in Figure 1a.

The pilot or control valve 85a likewise has a port 86a connected by means of a pipe 81a with a cylinder 88a at one end of the reversing valve 59a, and a port 89a from which a pipe 90a leads to a cylinder 9Ia at the opposite end of said reversing valve 59a. A port 92a of the pilot valve a communicates with a pipe 93a which in turn is connected with the low pressure line 68 for instance through the medium of the pipe 93, while another port 94a of said pilot valve 85a is connected by means of a branch connection 95a with the pipe 95 which leads back 'to the oil tank 96.

Similarly the pilot or control valve 85b is provided with a port 86b from which a pipe 87b extends to the cylinder 88b,at one end of the reversing valve 59b, and a second port 89b which is connected by means of a pipe b with the cylinder 9 I 12 located at the opposite end of the reversing valve 591). A third port 92b of the pilot valve 85b is connected by means of a pipe 93b with the low pressure line68, and a fourth port 941) thereof communicates with a pipe 9512 which leads back to the tank 96.

Ihe cylinders 88, 9| and 88a, 9Ia, and 88b and 9Ib of the respective reversing valves 59, 59a and 5912 are connected with the tank 96 by means of pipes 91, 98, 91a, 98a, 91b and 981), respectively as indicated diagrammatically in Figure 1.

Corresponding pilot or control valves 99 and 99a are provided for respectively controlling the operation of the hydraulically operated check valves 62 and 62a. An example of these valves is illustrated in Figure 15 later to be described in detail. As shown diagrammatically in Figure 1 the check valve 62 is provided at its opposite ends with cylinders I00 and IM respectively, the cylinder I00 being connected by means of a pipe I02 with the previously mentioned pipe line 60 to one side of the check valve 62, while the other cylinder MI is connected by means of a pipe I03 with said pipe line 60 on the other side of said check valve 62. In the preferred arrangement, a conventional check valve I04 is located in the pipe I82 as indicated in Figure 1. A connecting pipe I65 leads from the pipe I02 to a port I06 of the pilot valve 99 which has a second port I0'I connected by means of a pipe I08 with the high pressure line 66. In addition, the pilot valve 99 has two further ports I09 and I I0 which are connected with the previously mentioned tank 96 by a branch pipe I II as indicated in Figure 1. A port H2 of valve 99 is plugged.

The check valve 62a likewise includes two cylinders IBM and I8Ia located respectively at its opposite ends, the cylinder IUOa being connected by means of a pipe I05a with a port H2a of the pilot valve 99a, while a pipe I03a leads from the other cylinder I8Ia to the previously mentioned pipe line 601) on one side-of the hydraulically operated check valve 62a. As diagrammatically illustrated in Figure 1 a pipe I02a leads from a second port 1611 of the pilot valve 99a to said pipe line 6817 on the other side of said check valve 62a. The third port I0Ia of the pilot valve 99a leads to the high pressure line 66 through a pipe IBM. The pipe I02a is provided with a conventional check valve I04a of any customary type. Two additional ports I09a and I I0a of the pilot valve 99a are connected by means of a branch pipe 'IHa with the previously mentioned tank 96.

The pilot valves 85, 85a and 8517 are selectively operated by means of any suitable control operating system, a preferred system being shown in Figure 14 to be described later.

' The system further includes an auxiliary pump I I 3 of suitable type for returning leakage oil from the tank 96 to the low pressure line, said pump H3 accordingly being connected with said tank 96 by a pipe H4 and with the oil cylinder 82 of the low pressure accumulator C by means of a pipe H5 in which a check valve I I6 of conventional type is preferably located. The pump H3 is driven for instance by an electric motor III which preferably is automatically controlled by a float operated switch II'Ia located in the tank 96 and controlling the motor feed circuit H'Ib so as to start and stop the motor H1 in accordance with changes in the oil level in said tank 96.

The previously mentioned hydraulic variable delivery pumps II and Ila may be driven in any conventional manner as for instance by means of electric motors I I8 operatively connected with said pumps preferably through the medium of suitable speed reduction gearing H9 as diagrammatically illustrated in Figure 1a.

The pumps 'II and Ila, in the form shown in Figures 5 and 6 are of the well-known Waterbury type as shown for instance in United States 7 gles to the axis of the pump to various operative positions at inclinations thereto; in such pumps the setting of the tilting box determines the operative effect of the particular pump in question.

In the particular form of, such pumps illustrated in Figures 5 and 6, the tilting box is provided with a stud I26 which extends into a bushing I2I mounted in a bearing I22 in which said bushing I2I is capable of rocking. The bearing I22 is vertically movable lengthwise of a guide I23 and is carried by piston rods I24 and H25 projecting in opposite directions from said bearing I22 into cylinders I26 and I21 located in spaced opposed relation on the casing of the particular pump; the piston rods I24 and I25 are provided with pistons I28 and I29 which are respectively reciprocable in the cylinders I26 and I21 as illustrated in Figure 6. A set screw I30 may be provided on one of the cylinders, as for instance the cylinder I26, to constitute an adjustable abutment for arresting the movements of the pistons I28 and I29 in one direction when the tilting box is in its neutral position and to prevent adjustment of said tilting box in this direction beyond said neutral position.

The cylinder I26 of each pump 1I and Hat is provided with a port I3I connected by means of a pipe I32 with a port I33 of a pilot or control valve I34 similar in type to the pilot or control valves previously maintained herein and to be described in more detail hereafter. Similarly the cylinder I21 includes a port I3Ia from which a pipe I32a leads to a second port I33a of said pilot valve I34 which in addition has a port I35 connected by means of a pipe I36 with the low pressure line for instance by leading to the branch connection 8Ib as shown in Figure la, and another port I31 connected by means of a pipe I38 with the previously mentioned tank 96. The pilot valve I34 as illustrated in Figures 1a and 6- is automatically actuated in accordance with the amount of fluid in the accumulator A as will ap pear more fully hereinafter.

As shown in Figures la, 5 and 6, the port I33 of the pilot valve I34 is in communication with a pipe I32b which leads to the port Mil of an operating cylinder I4I forming part of a hydraulically controlled by-pass valve I42 with which each of the pumps H and Ilia is provided; each operating cylinder MI is further provided with a second port I43 which is connected at I44 with the casing of the associated pump 1! or 1m as shown in Figure 5. A piston I =35 is slidably mounted in the cylinder MI and is connected with a slide valve I46 slidably mounted in the independent cylinder I41 of each by-pass valve I42, the opposite ends of said cylinder I41 being connected by means of a channel I48. Each bypass valve I42 includes two ports I50 and I49 from which pipes I5I and I52 respectively lead to the associated pump casing so as to communicate respectively with the ports 10 and 15 of the pump H or with the corresponding ports 10a and 19a of the pump We; as the case may be.

The construction of the reverse valves 58, 59a and 53b is illustrated in Figures 1, 8 and 9. The valve 59 which is shown therein may be taken as illustrative and comprises an interior chamber I53 having its opposite ends in communication through a passage I5 iormed in .c valve body. A pair of spaced piston valve is and M56 are slidably mounted within a. re spider I5? and mounted upon a rod movement in unison. The spider rovided with slots iii, I18, and I19'which open into passages communicating with the valve ports 6Q, 65 and 58 resarcasm spectively. The chamber I53 and the passage I56 are in communication with the valve port 61. The rod I58 is connected to a piston I66 through the medium of an extension I86 at the left hand end of the valve rod I58. At the right hand end of the rod I58 a push rod IBI which is attached to the piston I59 abuts the rod I58. The net area of the piston I59 is somewhat larger than the area of the piston I63, while the stroke of the piston I59 is but half the stroke of the piston I60. Due to the effect of fluid pressure on the exposed right hand end of the valve rod I58, the valve is normally unbalanced toward the extreme left hand position. The areas of the pistons I56 and I60 are so chosen with respect to the net effective area of the end of valve rod I58 that whenever cylinder 9| is cut-off from the fluid pressure supply, the valves I55 and I56 move to the extreme left hand position thus connecting the port 64 with the port 65 and the port 58 with the port 61. Whenever fluid under pressure is admitted to both cylinder BI and cylinder 88, the piston I59 moves to the left through its full stroke and due to its greater area is able to prevent movement of the piston I60 to the right beyond mid-stroke, thus connecting the port 61 with both ports 64 and 58. Whenever pressure is applied to cylinder 9i alone, the valve is moved to the position shown in Figure 8 to connect port 65 with port 58 and port 64 with port 67.

The structural details of the hydraulically operated check valves 62 and 62a, both of which are of similar type, are shown in Figure 11, which for descriptive purposes illustrates specifically the check valve 62. As the check valve 62a is of corresponding arrangement, the following explanation will answer for both:

The ports 6i and 63 of the valve 62 communicate with the inner chamber I63 thereof, said chamber I63 being provided with a valve seat I64 located between the ports 6| and 63 for cooperation with the valve I65 to control the communication between said ports BI and 63. The valve I65 is carried by a rod I66 which projects in opposite directions from said valve I65 into connection with pistons I61 and I68 slidably mounted respectively in the cylinders I00 and MI. As shown in Figure 11 the piston I61 is preferably of greater crosssectional area than the piston I68. The check valve 62 is further provided with a port I 66 leading to the previously mentioned pipe 062 and a second port I'IU communicating with the previously mentioned pipe H13, said ports I66 and I1!) opening respectively into the cylinders IIJIJ and I III.

An example of the various pilot or control valves, 85, a, etc., referred to hereinbefore is illustrated in detail in Figure 10, the pilot valve 85 having been selected for descriptive purposes. As shown the pilot valve 85 includes an interior chamber I1 I, the opposite ends of which are connected with each other by means of a channel I12, it being understood that the previously mentioned ports 86, 89 and 94, all communicate with said chamber III, while the port 82 is in direct communication with a separate interior chamber I'Il as indicated in Figure 10. A pair of valve pistons H3 and I14 are mounted in spaced relation upon a stem-I15 and are slidably mounted in the chamber I1! in a manner to control the communication between the various ports, the valve H3 being of somewhat greater axial dimension than the valve I14 as shown in Figure 10. The

stem H5 projects outwardly beyond one end of the pilot valve in the form of a reduced rod I16 which is suitably connected with an operating linkage whereby the valves I13 and I14 are selectively adjusted to alter the communication between the ports 86, 89, 92, and 94. Thus in the right hand position, which is illustrated in Figure 10, communication is established between ports 88 and 92 and between ports 89 and 94. When the valve is moved to the left one-half of its movement, the port 89 is cut off from communication with port 94 and placed in communication with port 92 while ports 86 and 92 remain in communication as in the first position. When the valves are moved their full stroke to the left, the ports 89 and 92 remain in communication but port 88 is transferred from communication with port 92 to communication with port 94 through passage I12.

Referring now to Figure 13, there is illustrated the construction of the valve I34 which comprises a valve body I82 being formed therein an interior bore I83, the opposite ends of which are in communication through a passage I84. Within the bore I 83 there is slidably mounted a valve member comprising pistons I85 and I86. The ports I33, I33a, I35 and I31 communicate with the bore I83 in the manner illustrated so that whenever the valves I85 and I86 are moved to the right handposition, as shown, communication is established between the ports I31 and I 33a and between the ports I35 and I33. When the valve is moved to the left hand position, the connection of the ports is reversed so that port I33 is placed in communication with port I31 through the passage I84, and port I35 is placed in communication with the port I 33a.

The valve I34 is operated in accordance with the level of fluid in the accumulator A, the construction of which is diagrammatically illustrated in Figure 12. Thus the accumulator proper 15 may comprise a base I81 having centrally positioned thereon a hollow piston I88. Surrounding the piston I88 there is provided a vertically movable oil cylinder I89 within which the oil to be accumulated is stored. The upper end of the cylinder I89 reciprocates within a bore I90 formed in the bottom of an air chamber I 9| which is supported from the base I81 by means of uprights I92. The air chamber I9I is in communication with the air storage reservoir 16 through a conduit 11, it being understood that suitable mechanism, not shown, may be provided for initially establishing and maintaining a suitable pressure upon the air within the reservoir 16 and the chamber I9l The conduit 14 extends through the base I81 to communicate with a passage I formed in the piston I88. In order to control the valve I34 a bracket I96 is secured to the bottom of the cylinder I89 and carries at its outer end a vertical rod I91 which is slidably mounted in a bracket I98. The rod I91 carries a pair of adjustable stops I99 and 200. A bell crank 20I is pivoted in a bracket 202 and has one arm thereof in juxtaposition to the rod I91 for actuation by the stops I99 and 200, while the other arm thereof is connected to actuate the operating rod 203 of the valve I34.

The construction of the valves 99 and 99a is illustrated in Figure 15. The valve 99, which may be taken as illustrative, is provided with an interior bore 204 within which is slidably mounted a valve member 205 carrying a pair of piston valves 206 and 201. The ports I06, I01, I09, H0 and H2 open directly to counterbores in the bore 204 in such positions that when the valve is in the right hand position, as illustrated, the port I06 is in communication with port I09, while the port I I2 is in communication with the port I01. When the valve is moved to the left, the connections are in effect reversed and port I08 is placed in communi- 5 cation with port I 01 while port H2 is placed in communication with port I I 0.

Referring now to Figure 14, the connections by which the various pilot or control valves are operated in proper sequence are shown diagrammatically. A starting handle 208 is pivotally mounted in a bracket 209 and has rigidly secured thereto a pair of arms 2I0 and 2. The handle 208 and associated arms are movable between three positions indicated by the dot-dash lines. The arm 2I0 carries a roller 2 I2 through which a vertically adjustable cam 2I3 mounted on the first blank holder I1 may actuate the handle 208 from position number 2 to position number 3, at any selected point in the downward movement of the blank holder. The arm 2 is connected to actuate the operating rod of the valve 85, a spring 2 I4 normally holding the valve in right hand position. Depending from the arm 2 I 0 is a link 2 I 5 having a notch 2| 6 which is engageable with the latch 2I1 2- when the handle 208 is moved from position number 2 to position number '3. The latch 2I1 is actuated through a bell crank 2 I8 and link 2 I9 by a vertically adjustable trip 220 mounted upon the auxiliary blank holder I 8. The trip 220 is constructed to pass the bell crank 2I8 without actuating' the same on the downward movement, while upon upward movement of the blank holder I8, the bell crank is actuated to trip the latch 2 I 1 and permit the valve 85 and associated mechanism to 3 move to position number 1 under the urge of spring 2 I4. The first blank holder I1 also carries a vertically adjustable trip 22I which is adapted to actuate at a predetermined point in the downward movement of the blank holder a bell crank 222 from position number 1 to position number 2. Bell crank 222 is connected to the operating rod of the valve 85a and is normally held in position number 1 by a spring 223. v A link 224 depending from the bell crank 22' has a notch 225 which may be engaged by a latch 228. The latch 228 is carried upon a link 221 which in turn is mounted on a lever 228 pivoted at 229. When the bell crank 222 is moved from position number 1 to position number 2 by the trip 22I, the latch"22 6 engages the notch 225 and connects the links 224 and 221 together. The arm 228 is adapted to be depressed by an adjustable cam 230 mounted on the auxiliary blank holder I8 whereby the links 224 and 221 may be actuated downwardly to move valve 85a from position number 2 to position number 3 where it is adapted to be latched by a latch 23I engaging in a notch 232 in the link 221. The latches 226 and 23I are releasable by an adjustable trip 233 mounted upon an extension 234 of the table I9.

The valve 851) has its operating rod connected to a lever 235 pivoted at 236 and connected by means of a link 231 to a bell crank 238-and a slide 239. A spring 240 normally maintains the valve 85b and associated mechanism in position number 1. The bell crank 238 is pivoted at 24I and carries a roller 242 engageable with an adjustable trip 243 mounted on the auxiliary blank holder I8 for actuation of. the valve 85b from position number 1 to position number, 2 at a predetermined point in the downward movement of the auxiliary blank holder I8. The bell crank 238 also carries a depending link 244 having a notch 245 engageable with a 15 latch when in position number 2. The latch 2% is carried by a second link 25 1] having a notch engageable with a latch E ia when in position number 3. The latches 256 and 259 are connected by a slotted link 25811 by which a spring 25% may urge latch 2% into the notch 2&5. The latch 2% is biased by its own weight toward the notch and is movable clockwise suificiently for the upper end thereof. to abut the upper end of latch 2% so that both may be released together. The valve 851; is movable from position number 2 to position number 3 through the links 2 3 and E li by a lever which is engageable with the vertically adjustable trip 253i mounted upon the table iii.

The valve 99a is actuated by the slide through the medium of a lever 252 pivoted in a bracket and is normally held to the left by a spring The slide 239 engages the lever moves the valve 99a to the right when lever is moved from position number 2 to position number 3. The valve as is normally held to the right by a spring 2555 and is actuatable to the left through the medium of a bell crank 25b pivoted in a bracket 255i and a vertically adjustable cam carried by the extension 23 on the table it. The cam 258 may be adjusted downwardly to such a position that it will not be operative upon the bell crank 256 if desired.

In operation of the mechanism heretofore described the various adjustable trips and cams associated with the blank holders ill and it and the table l9 and which are illustrated in Figure 14 being adjusted to produce a desired cycle of operations and the press being fitted with suitable dies, the starting handle 208 is moved from position number 1 to position number 2. This movement operates valve 65 to the mid-position wherein ports Q2, 86 and 89 thereof are placed in communication. Fluid from the intermediate pressure line 6% will then flow through the conduit 93, valve 85, conduits 90 and ill to the cylinders 91! and 38 respectively. The application of fluid under pressure to both cylinders 8t and Si simultaneously, places the valve 59 in the mid-position. wherein the ports 64 and 58 are in communication with the port iil. Fluid from the intermediate pressure line 68 is thus permitted to flow through the conduits (iii and 57 to the return cylinder M- and the operating cylinder 42. Check valve 62 is maintained open at this time since the valve bil is maintained in the right hand position by the spring 255. Due to the larger area of the ram Ll El the first blank holder ll advances downwardly at a rapid rate and at a low pressure. As soon as the adjustable cam 2E3 comes in contact with the roller 2 E2 the valve 35 is moved from position number 2 to position number 3 for transfer of the blank holder ll from low pressure advance oper ation to high pressure advance.

The movement of valve 85 to the left hand position, that is position number 3, establishes communication between the ports 92 andilil and also between the ports 94 and 86. Intermediate pressure fluid from the line 68 is thus permitted to flow to the cylinder Ell while the cylinder dd is exhausted through the line 8i, valve 35 and line $5 to the tank. Valve 58 is thus moved to the right hand position and high pressure fluid is permitted to flow from the line 66 through valve 59 and. line St to the operating cylinder Q2. The fluid exhausted from the return cylinder 3 i flows through line 60, valve it, to the intermediate pressure line 68. The blank holder ll thus advances downwardly under high pressure to the end or its stroke. At a predetermined point in the move,- ment of the blank holder ill which may be either before or after the change from low pressure advance to high pressure advance, the trip 22H engages the bell crank and moves the valve Elba from the right hand position to the mid-position; that is, from position number 1 to position number 2. The auxiliary blank holder it is thereupon caused to advance at a rapid rate under low effective pressure in the same manner that blank holder holder ill was operated when valve was placed in position number 2. Upon a predetermined downwardly advance of the blank holder the cam 23b engages the lever to move valve 85a from position number 2 to position number 3, thus transferring the second blank holder from low pressure advance to high pressure advance in a manner analogous to that previously described. The valve 35a is maintained in posi tion number 3 by the latch 23H. At a predetermined point in the downward movement of the blank holder it, the trip 2:33 engages the roller 2E2 to move valve 8% from position number 1 to position number 2, thus initiating low pressure ad- Vance upwardly oi the table it; the sequence of operation of the valves 85b and 591) being similar to that of the valves 85 and 59 previously described.

Upon a predetermined upward advance of the table it the trip actuates the lever in to pull the valve $5?) from position number 2 to position number 3, thus changing from low pressure advance to high pressure advance of the table l9. At the completion of its stroke the effective half of the operating cycle is completed and the two blank holders and table stall against one another with the work between the dies.

The return cycle is initiated by manually or otherwise releasing the latches 2% and 269 bymoving the latter clockwise which permits the valve 351) to move from position number 3 to position number 1 under the influence of spring 24c. Fluid from the intermediate pressure line 68 is thus permitted to pass through the line @317 to line Mb and cylinder @Eb, while the cylinder Qlb is exhausted to the tank through line 9131), port 8912 and port Mb. The hydraulic bias of the valve 59b thus causes it to move to the left hand position wherein ports 65?) and b ll; are connected and ports dllb and 5812 are connected, thus admitting high pressure fluid from the line 66 to the line 6th and the return cylinder 56. After the table lit has returned a predetermined amount, trip 233 actuates the latch 23! to permit valve 85a to move to position number 1 under the influence of spring The auxiliary blank holder i8 is thus started on its return stroke in a manner similar to that previously described in connection with the table it. At a predetermined point in the upward return of the blank holder, the trip 22b releases the latch ill? permitting the valve 85 to return to position number 1 under the influence of spring 2M and the blank holder ll is thus started on its return stroke. Upon completion of the return strokes the three elements of the press become stalled against suitable stops and are maintained in this position by the pressure in the return cylinders until the handle 2% is again actuated to initiate a cycle of operation.

The valve We is operated When valve 85b moves from position number 2 to position number 3 by pressure fluid is thus admitted from the line 66 through line I08a through the ports M111 and I I2a and line I05a to the cylinder I00a. The check valve 62a is thus closed to prevent the admission of intermediate pressure fluid through the line 60b to the return cylinders 56. The valve 89a simultaneously opens communication between the.

table I9 which is prior to .the completion of its stroke but subsequent to the completion of'the stroke of the first blank holder II. With the cam258 thus adjusted, the valve 99 is actuated from right hand position to left hand position after the blank holder I! has completed its stroke and communication is thus established from the high pressure line 66 through line I08, port I01, port I06, line I05, check valve I04, and line. 60, to the return cylinder 44. Thispath is restricted in comparison to the line 60 so that the fluid is admitted'to the cylinder 54 in restricted quantities, just suflicient to break the toggle linkage for the blank holder II, after which the blank holder I1 is returned byv force transmitted from the table [9 to the blank holder I'I through the dies and the work. Upon completion of the advance stroke of the table I9, the blank holder I'I continues to ad- Vance at a low rate from the pressure fluid supplied through the line I05 until the cam 258 drops to the point where bell crank 256 may move valve 99 to the right hand position under the influence of spring 255.

It will be understood that the settings of the. various cams and trips may be changed to produce,

a wide variety of cycles of operation of the press as a whole and that a suitable adjustment will. be

-selected for any stamping operation which it is desired to perform in the press. At all times when the press is in operation the pressure in the line 66 is maintained substantially constant by under the influence of the volume of fluid stored in the accumulator system A. Thus, when the cylinder I89 is filled with fluid and as a consequence has moved upwardly into the air chamber 15,,the stop 200 engages the bell crank 20I to move the valve I34 from the right hand position to the left hand position. The ports I33 and I33a are placed in communication wtih the ports I31 and I35 respectively in the left position of valve I34. Fluid is thus admitted from the intermediate pressure line 8") to the line I36, valve I34, line I32a, and cylinder I21, thus actuating the piston I29, and the tilting box stub shaft I20, to the position of zero stroke. At the same time the cylinders I26 and HI are exhausted to the tank through lines I32b and I32, valve I34 and line I38. By-pass valve I46 is then permitted to move upwardly in Figure 5 under its hydraulic bias to connect the ports I49 and I50, and thus shunt the outlet 69 and th inlet I6 of the pump. Similar action takes pla e upon the corresponding mechanis'm of the pump Ila.

Whenever the fluid stored in the cylinder I89 is depleted, the stop I99 moves the valve I34 to the right hand position in which the connections are reversed, and fluid under pressure is admitted to line I32 and cylinder I26 to move the tilting box to full stroke position and thrdugh line I32b to the cylinder I to move the by-pass valve I46 to closed position..

The intermediate pressure accumulators B and C are similar to the accumulator system A ex-' cept no provision for actuating a valve analogous to the valve 1I34 is made. These accumulators act toprovide a reservoir of intermediate pressure fluid to take care of peakdemands upon the system made by the principal actuating cylinders of the press as well as the control system.

It will thus be seen that the present invention provides a hydraulic operating system for a multiple action press wherein the advantages of hydraulic operation may be obtained in presses of very large size without necessitating unreasonable size and excessive cost in the fluid pumps rethe combination ofa variable displacement, unidirectional delivery, fluid pump,'a prime mover for operating the pump, an intermittently operating hydraulic motor fed by the pump, an accumulator for storing variable amounts of fluid under pressure and means for controlling the displacement of the pump in response to variations in the amount of fluid stored in the accumulator, said means operating upon an increase in the quantity of fluid stored in the accumulator, to decrease the pump displacement, and upon a decrease in the quantity of fluid stored in the accumulator to increase the pump displacement, and means energized concurrently with the displacement varying means for by-passing the pump when not 'operating'at full displacement.

2. In a hydraulic power transmission the combination of a closed fluid circuit'having a high pressure portion, an intermediate pressure portion and a low pressure portion, a first pumping means for transferring fluid from the low pres- I 'sure portion to the intermediate pressure portion, a second pump for transferringfluid from the intermediate pressure portion to the high pressure portion, a fluid motor, means for selectively op-- erating the motor at either of two different pressure differentials, and means for accumulating fluid under pressure delivered by each pumping means while the motor is operating on fluid delivered by the other pumping means.

8. In a hydraulic power transmission the combination of a closed fluid circuit having a high pressure portion, an intermediate pressure portion and a low pressure portion, a first pumping means for transferring fluid from the low pressu e portion to the intermediate pressure portion, a second pump for transferring fluid'from the intermediate pressure portion to the high pressure portion, a reversible fluid motor, means for selectively operating the motor in either direction and in one direction at either of two different pressure diflerentials, and means for accumulating fluid under pressure delivered by each pumping means while the motor is operating on fluid delivered by the other pumping means.

4. In a hydraulic power transmission the combination of a closed fluid circuit having a high pressure portion, an intermediate pressure portion and a low pressure portion, a first pump for transferring fluid from the low pressure portion to the intermediate pressure portion, a second pump for transferring fluid from the intermediate pressure portion to the high pressure portion, a first fluid motor, a second fluid motor, means for operating the first motor at one pressure difierential, means responsive to a predetermined movement of the first motor for operating the first motor at a second pressure differential, and means responsive to a predetermined movement of the first motor for operating the second motor.

5. In a hydraulic power transmission the combination of a source of fluid under pressure, a fluid motor, means forming a comparatively unrestricted conduit between the source and the motor, means forming a restricted conduit be tween the source and the motor, a valve for controlling fluid flow in the first conduit, a second valve for controlling fluid flow in the second con duit, and a separate valve operating motor iorone of the valves responsive to pressure admitted to one of the conduits by the other valve.

6. In a hydraulic power transmission the combination of a closed fluid circuit having a high pressure portion, an intermediate pressure portion and a low pressure portion, a first pumping means for transferring fluid from the low pressure portion to the intermediate pressure portion, a second pumping means for transferring fluid from the intermediate pressure portion to the high pressure portion, a fluid motor, means for selectively operating the motor at either of two different pressure differentials, and means for accumulating fluid under pressure delivered by the second pumping means while the fluid motor is operating from the first pumping means.

7. In a hydraulic power transmission the combination of a closed fluid circuit having a high pressure portion, an intermediate pressure portion and a low pressure portion, a first pumping means for transferring fluid from the low pressure portion to the intermediate pressure portion, a second pumping means for transferring fluid from the intermediate pressure portion to the high pressure portion, a reversible fluid motor, means for selectively operating the motor in either direction and in one direction at either of two different pressure diiferentials, and means for accumulating fluid under pressure delivered by the second pumping means while the fluid motor is operating from the first pumping means.

8. In a hydraulic power transmission the combination of a closed fluid circuit having a high pressure portion, an intermediate pressure portion and a low pressure portion, a first pumping means for transferring fluid from the low pressure portion to the intermediate pressure portion, a second pumping means for transferring fluid from the intermediate pressure portion to the high pressure portion, accumulator means for storing and releasing a substantial quantity of fluid in the intermediate pressure portion, aocumulator means for storing and releasing a substantial quantity of fluid in the high pressure area-e47 portion, and intermittently operating fluid motor means operable selectively from either the high pressure portion or the intermediate pressure portion and with a fluid consuming capacity substantially greater than the delivery capacity of either pumping means but no greater than the delivery capacity of the pumping means and associated accumulator means together.

9. In a'hydraulic power transmission circuit the combination of a fluid pump, a prime mover for operating the pump, an intermittently operating hydraulic motor fed by the pump, and having interconnected oppositely acting expansible chambers of different displacements, accumulator means associated with both the inlet side and outlet side of the pump for storing variable quantitles of fluid at different constant pressures, means for maintaining the inlet side of the pump above atmospheric pressure, and valve means between the accumulator means and the fluid motor operable selectively to either connect both chambers of the motor to the inlet side for rapid low pressure advance of the motor, or to connect the larger chamber to the outlet side and the smaller chamber to the inlet side for slower high pressure advance or to connect the smaller chamber to the outlet side and the larger chamber to the inlet side for rapid lower pressure return, the ratio of the larger chamber displacement to the smaller chamber displacement being less than the ratio of the outlet side pressure to the inlet side pressure.

10. In a hydraulic power transmission circuit the combination of a fluid pump, a prime mover for operating the pump, an intermittently operating hydraulic motor fed by the pump, and having interconnected oppositely acting expansibl'e chambers of difierent displacements, accumulator means associated with both the inlet side and outlet side of the pump for storing variable quantities of fluid at different constant pressures, means for maintaining the inlet side of the pump above atmospheric pressure, and valve means between the accumulator means and the fluid motor operable selectively to either connect both chambers of the motor to the inlet side for rapid low pressure advance of the motor, or to connect the larger chamber to the outlet side and the smaller chamber to a point of lower pressure for slowerhigh pressure advance or to connect the smaller chamber and larger chambers to points of respectively high and low pressures for rapid lower pressure return, the ratio of the larger chamber displacement to the smaller chamber displacement being less than the inverse ratio of their respective operating pressures during the return stroke.

11. In a hydraulic power transmission circuit the combination of a fluid pump, a prime mover for operating the pump, an intermittently operating hydraulic motor fed by the pump, and having interconnected oppositely acting expansible chambers of difierent displacements, accumulator means associated with both the inlet side and outlet side of the pump for storing variable quantities of fluid at dfierent constant pressures, an expansion tank at atmospheric pressure, means for maintaining the inlet side of the pump above atmospheric pressure, by transferring fluid from the expansion tank to said inlet side, and valve means between the accumulator means and the fluid motor operable selectively either connect both chambers of the motor to the inlet side for rapid low pressure advance of the motor, or to connect the larger chamber to the outlet side and the smaller chamber to said expansion tank for slower high pressure advance or to connect out of a working position by the first fluid motor,

a second fluid motor, a second reciprocating load device to perform a working stroke in opposition to the first load device, means operatively connecting the second fluid motor to the second load device, a toggle linkage for operatively connecting the first fluid motor to the first load device and arranged to lock against back thrust on the load device when the first load device is in work ing position, means for supplying pressure fluid to the first motor for bringing the first load device into working position, means for supplying pressure fluid to the second motor for imparting a working stroke to the second load device to exert a thrust against the first load device, and adjustable means for rendering said toggle effective or ineffective to resist the thrust of said second load device.

13. In a hydraulic power transmission circuit the combination of a first fluid motor, a first reciprocating load device to be brought into and out of a working position by the first fluid motor, a second fluid motor, a second reciprocating load device to perIorm a working stroke in opposition to the first load device, means operatively connecting the second fluid motor to the second load device, a toggle linkage for operatively connecting the first fluid motor to the first load device and arranged to lock against back thrust on the load device when the first load device is in working position, means for supplying pressure fluid to the first motor for bringing the first load device into working position, means for supplying pressure fluid to the second motor for imparting a Working stroke to the second load device to exert a thrust against the first load device, and adjustable means for causing said first motor to retract the toggle whereby the first load device may be made to either resist the thrust of the second load device or to yield to the same.

14. In a hydraulic power transmission circuit the combination of a source of fluid under pressure, a member reciprocable between three fixed positions, a first fluid motor for moving the member from one extreme position to the other extreme position, a second fluid motor for moving the member from the other extreme position to mid position, and having a larger effective area than the first motor, means biasing the member to the first extreme position, and means for controlling the admission of fluid from said source to said motors and operable to disconnect both motors from said source whereby the member remains inthe first extreme position,

to connect both motors to said source whereoy the member is moved to mid position, and to connect only the first motor to said source whereby the member is moved to said other extreme position.

ARTHUR L. ELLIS. 

